Conventionally, the so called Czochralski method has been widely adopted for producing a single crystal material such as a single crystal semiconductor material. This is a method in which polycrystalline silicon is melted in a container, and an end of a seed crystal is dipped into the melt bath (melt) and is pulled with rotation. In this method, a single crystal grows under the seed crystal with having the same crystal orientation. In pulling of a single crystal silicon, a quartz glass crucible is generally used for the container from which the single crystal is pulled.
When polysilicon is melted in a quartz glass crucible to pull a single crystal silicon, there partially occurs a brown circular crystal called brown ring on the inner surface of the quartz glass crucible, which is amorphous. This brown ring is partial and very thin, thereby being liable to exfoliate during pulling of a single crystal silicon. This exfoliated piece can be incorporated into the single crystal silicon ingot to be pulled to lower the crystallinity of the single crystal silicon as a common phenomenon that occurs generally.
To solve the foregoing problem, for example, Patent Document 1 discloses an art in which a crystallization promoting agent is added into the inner surface of a crucible to crystallize the whole region of the inner surface of the crucible, thereby improving the strength of the crucible while suppressing the generation of a brown ring. In this art, however, impurities contained in the crystallization promoting agent are incorporated into the single crystal silicon to lower the crystallinity.